2,269 research outputs found
The variation in pressure in the cabin of an airplane in flight
The pressure in the cabin of a Fairchild cabin monoplane wa surveyed in flight, and was found to decrease with increased air speed over the fuselage and to vary with the number and location of openings in the cabin. The maximum depression of 2.2 inches of water (equivalent pressure altitude at sea level of 152 feet) occurred at the high speed of the airplane in level flight with the cabin closed
Effect of the Angular Position of the Section of a Ring Cowling on the High Speed of an XF7C-1 Airplane
The tests herein reported were conducted by the NACA to determine the effect of the angular position of the section of a ring cowling on the speed of an airplane having a radial air-cooled engine
The Effect of Fillets Between Wings and Fuselage on the Drag and Propulsive Efficiency of an Airplane
Tests were made to determine the effect of fillets between wings and fuselage on the drag and propulsive efficiency of a high-wing cabin monoplane. These tests were made in the 20-foot Propeller Research Tunnel of the National Advisory Committee for Aeronautics
Methods of Visually Determining the Air Flow Around Airplanes
This report describes methods used by the National Advisory Committee for Aeronautics to study visually the air flow around airplanes. The use of streamers, oil and exhaust gas streaks, lampblack and kerosene, powdered materials, and kerosene smoke is briefly described. The generation and distribution of smoke from candles and from titanium tetrachloride are described in greater detail because they appear most advantageous for general application. Examples are included showing results of the various methods
Computational Dynamics of a 3D Elastic String Pendulum Attached to a Rigid Body and an Inertially Fixed Reel Mechanism
A high fidelity model is developed for an elastic string pendulum, one end of
which is attached to a rigid body while the other end is attached to an
inertially fixed reel mechanism which allows the unstretched length of the
string to be dynamically varied. The string is assumed to have distributed mass
and elasticity that permits axial deformations. The rigid body is attached to
the string at an arbitrary point, and the resulting string pendulum system
exhibits nontrivial coupling between the elastic wave propagation in the string
and the rigid body dynamics. Variational methods are used to develop coupled
ordinary and partial differential equations of motion. Computational methods,
referred to as Lie group variational integrators, are then developed, based on
a finite element approximation and the use of variational methods in a
discrete-time setting to obtain discrete-time equations of motion. This
approach preserves the geometry of the configurations, and leads to accurate
and efficient algorithms that have guaranteed accuracy properties that make
them suitable for many dynamic simulations, especially over long simulation
times. Numerical results are presented for typical examples involving a
constant length string, string deployment, and string retrieval. These
demonstrate the complicated dynamics that arise in a string pendulum from the
interaction of the rigid body motion, elastic wave dynamics in the string, and
the disturbances introduced by the reeling mechanism. Such interactions are
dynamically important in many engineering problems, but tend be obscured in
lower fidelity models.Comment: 17 pages, 14 figure
Lagrangian Mechanics and Variational Integrators on Two-Spheres
Euler-Lagrange equations and variational integrators are developed for
Lagrangian mechanical systems evolving on a product of two-spheres. The
geometric structure of a product of two-spheres is carefully considered in
order to obtain global equations of motion. Both continuous equations of motion
and variational integrators completely avoid the singularities and complexities
introduced by local parameterizations or explicit constraints. We derive global
expressions for the Euler-Lagrange equations on two-spheres which are more
compact than existing equations written in terms of angles. Since the
variational integrators are derived from Hamilton's principle, they preserve
the geometric features of the dynamics such as symplecticity, momentum maps, or
total energy, as well as the structure of the configuration manifold.
Computational properties of the variational integrators are illustrated for
several mechanical systems.Comment: 19 pages, 7 figure
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